Dear All,
Hello. I have a question about SATA_CAP Register in i.MX6DQ.
Refer to bit:28 SMPS & bit:27 SSS of "53.7.1 HBA Capabilites Register (SATA_CAP)" in IMX6DQRM(Rev.3).
There are below descriptions.
- bit:28 SMPS
"This bit is set by the system firmware/BIOS when the platform supports mechanical presence switch for
hot plug operation."
- bit:27 SSS
"This bit is set by the system firmware/BIOS to indicate platform support for staggered devices' spin-up."
These two bits seems to be possible to write by software.
But, this bits are read only.
Is it possible to write to these bits by software?
Best Regards,
Keita
Solved! Go to Solution.
HI Keita
these are not typo, just generic IP module description.
Description says:
"when the platform supports..."
I.MX6 platform does not support these features,
it is not implemented on i.MX6 paltform.
Other platforms (not i.MX6) may have this implemented.
Best regards
igor
HI Keita
these are read only bits, describing capabilities of SATA module
which are defined at synthesis level of this DesignWare SATA IP module.
So SMPS describes that there is no dedicated mechanical switch for
sata device presence (it is not impelmented for i.MX6 IP synthesis).
SSS describes that "staggered devices spin-up" is not used for i.MX6
SATA module implementation. Note, staggered devices spin-up is used for
multiple devices power-up, while i.MX6 SATA module connects one SATA device.
Spin-up - Wikipedia, the free encyclopedia
Best regards
igor
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Hi Igor,
Thank you for your reply.
Let me clarify my understanding.
===
It is Read only bit and i.MX6 isn't use the bit.
But, BSP, BIOS and Firmware can use this bit as Read/Write.
===
Is my understanding OK?
Best Regards,
Keita
HI Keita
It is read only bits and nobody can write it:
nor i.MX6, nor BSP or other software
Best regards
igor
Hi Igor,
Thank you for you reply.
If your answer is correct, below descriptions look typo.
====
- bit:28 SMPS
"This bit is set by the system firmware/BIOS when the platform supports mechanical presence switch for
hot plug operation."
- bit:27 SSS
"This bit is set by the system firmware/BIOS to indicate platform support for staggered devices' spin-up."
====
Best Regards,
Keita
HI Keita
these are not typo, just generic IP module description.
Description says:
"when the platform supports..."
I.MX6 platform does not support these features,
it is not implemented on i.MX6 paltform.
Other platforms (not i.MX6) may have this implemented.
Best regards
igor
HI Keita
even these bits are written, they have not
effect on chip because these features are not
implemented in synthesis level.
Best regards
igor
Hi Igor,
Thank you for your quick response.
OK. I got it.
Keita